diff --git a/demos/gtk-demo/offscreen_window2.c b/demos/gtk-demo/offscreen_window2.c
index 5c16c4051a..a9d1687087 100644
--- a/demos/gtk-demo/offscreen_window2.c
+++ b/demos/gtk-demo/offscreen_window2.c
@@ -345,7 +345,7 @@ gtk_mirror_bin_get_preferred_height (GtkWidget *widget,
 
   gtk_mirror_bin_size_request (widget, &requisition);
 
-  *minimum = *natural = requisition.width;
+  *minimum = *natural = requisition.height;
 }
 
 static void